Catfish Special Edition: Thermal Inactivation of Non-O157:H7 Shiga Toxin Producing Escherichia coli (STEC) on Catfish Fillets
- *Corresponding Author:
- Shiowshuh Sheen
Eastern Regional Research Center
Agricultural Research Services
United States Department of Agriculture
Wyndmoor, Pennsylvania, USA
E-mail: [email protected]
Received Date: June 10, 2013; Accepted Date: June 15, 2013; Published Date: June 20, 2013
Citation: Khosravi P, Silva J, Sommers CH, Sheen S (2013) Catfish Special Edition: Thermal Inactivation of Non-O157:H7 Shiga Toxin Producing Escherichia coli (STEC) on Catfish Fillets. J Food Process Technol S11:006. doi: 10.4172/2157-7110.S11-006
Copyright: © 2013 Khosravi P, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Non-O157:H7 shiga toxin-producing Escherichia coli (non-O157 STEC) strains have emerged as food borne pathogens which have been involved in numerous food borne illness outbreaks worldwide. Seafood (fish) consumption has increased in recent years: it could become more common that STEC outbreaks may be associated with the non-O157 serovars. However, there is a lack of data on thermal inactivation of non-O157 STECs in fish muscle (e.g. catfish). Catfish fillets were inoculated with a six-isolate cocktail of non-O157 STEC serovars, i.e. O26:H11, O45:H2, O103:H2, O111:NM, O121H19, and O145:RM (the Big 6), to determine the impact of thermal treatment (heat) on their survival or thermal inactivation kinetics. The inoculated catfish fillet samples (108-9 cfu/g) were subjected to isothermal heating at 55, 60, and 65°C. The D- and z- values were determined by using linear regression of the survival data. The D- values were found to be 712 sec (R2 = 0.88), 38.8 sec (R2 = 0.97) and 3.6 sec (R2 = 0.91) at 55, 60 and 65°C, respectively. The z-value was 4.4°C, consistent with reported values for STECs in other food systems. The results of this study showed that the thermal inactivation effect of non-O157 STECs is not the same as of O157 strains in catfish meat, especially at lower temperature (e.g. 55°C), but becomes similar as temperature increases. The findings will assist risk assessors in providing safer finfish products to consumers.